The present invention is directed to bicycle brake devices and, more particularly, to bicycle brake devices that are used to brake a hub of a bicycle wheel.
Bicycle braking devices currently available include rim braking devices and hub braking devices. Rim braking devices include cantilever brakes or caliper brakes that brake the rim of the wheel. Hub braking devices brake the wheel hub, and they include drum brakes, band brakes, roller brakes and the like. A hub brake brakes the hub of the wheel, so it is able to provide braking even if the wheel rim is warped.
Conventional bicycle hub brake devices comprise a fastening bracket nonrotatably mounted to the bicycle frame, a brake drum that rotates integrally with the hub, brake shoes that provide a braking action on the brake drum, and a brake operating component for bringing the brake shoes into pressed contact with the braking surface of the brake drum. A front end portion of the fastening bracket is secured to the bicycle frame, such as the front fork or a rear chain stay, and a base portion of the fastening bracket is secured to the hub shaft. The brake shoes are nonrotatably mounted relative to the fastening bracket. A bracket retaining component may be formed on the fastening bracket or on a cover member attached to the fastening bracket so as to prevent the brake drum from failing off of the fastening bracket when attaching or detaching the brake device. The bracket retaining component also allows the brake drum to be attached to and detached from the bicycle frame along with the fixing bracket.
More specifically, a diametrically outwardly protruding annular protrusion may be formed on the outer peripheral surface of the brake drum, wherein the annular protrusion engages the bracket retaining component. A plurality of clasps may be formed on the base portion of the mounting bracket, wherein the clasps may be bent so that the tips of the clasps face the annular protrusion formed on the brake drum and thereby serve as the bracket retaining component for retaining the brake drum to the fastening bracket. When a cover member is provided for covering the base portion of the fastening bracket facing away from the brake drum, a plurality of clasps may be disposed on the cover member to secure the cover member to the base portion of the fastening bracket. The clasps may be bent so that the tips of the clasps face the annular protrusion formed on the brake drum and thereby serve as the bracket retaining component for the brake drum as well.
The cover member must be removed when disassembling the brake device for inspection, repair, or the like. Because the base of the clasps arc reversibly deformed to remove the cover, a resulting danger is that repeated disassembly can lead to fatigue and thus breakage of the base of the clasps. The cover member must be replaced if a clasp formed on the cover member breaks. As the cover member is a relatively expensively designed and coated part, its breakage is uneconomical. The same is true when clasps are provided on the fastening bracket to retain the brake drum to the fastening bracket. That is, the fastening bracket must be replaced when a clasp is broken. Since the fastening bracket is even more expensive to replace than he the cover member, the effect is very undesirable.
The present invention is directed to inventive features of a bicycle braking device. In one embodiment, a bicycle hub brake component is provided for braking a hub of a wheel mounted on a bicycle frame. The component comprises a fastening bracket that has a first surface and a second surface opposite the first surface, wherein the fastening bracket is adapted to be nonrotatably mounted to the frame. A brake drum is adapted to rotate integrally with the hub, wherein the brake drum has a brake face on an inner peripheral surface thereof and a convex portion adapted to face the first surface of the fastening bracket. A bracket retaining component is removably mounted to the fastening bracket and extends diametrically so as to engage the convex portion to help prevent the brake drum from detaching from the fastening bracket. Additional inventive features will become apparent from the description below, and such features alone or in combination with the above features may form the basis of further inventions as recited in the claims and their equivalents.